Many windows are located in publicly accessible places. Yet, it may be undesirable for the windows to be situated so that anyone can operate the windows to open and close them at any time. Unauthorized opening of windows may permit unauthorized access to the building and can also create safety concerns particularly in buildings where children are present. Accordingly, various schemes are available so that a window may be locked in either an open, closed or partially open condition and can only operated by authorized persons such as custodians.
A casement or an awning window generally refers to a sash that is attached to its frame by one or more hinges. The hinges can be located on any side of the sash and the frame though generally not on the lower edge of the sash and frame. In general, a casement window rotates along a horizontal plane (the hinges of a casement window defining a vertical rotation axis), while an awning window rotates along a vertical plane (the hinges of an awning window defining a horizontal rotation axis). Most casement and awning windows which employ the use of a crank lever or cam handle operator open outwardly so as not to interfere with the operator of the window.
An advantage of many casement and awning windows is that substantially the full window opening can be exposed without requiring the removal of the window from the frame. In contrast, for example only half of the opening of a double-hung window can be exposed by raising the lower sash or lowering the upper sash. The sashes of double hung or horizontally sliding windows must be completely removed from the frame to expose the entire window opening
Window operators for casement or awning windows often have a folding handle that is freely moveable from a folded position in which the handle is nestled into a cover of the operator to an operating position in which the handled is movable to crank the window open or closed.
There exists, in the prior art, a casement or awning window operator with a folding handle and a cover with a key cylinder located in the cover. Rotation of the key approximately 180° actuates a sleeve that can be extended and retracted. When in the extended position, the sleeve covers a part of the handle knob thus preventing the handle from being moved from a folded position to an operating position in which it may be used as a crank to open and close the window. According to the prior art, the sliding sleeve is actuated by a pin at the end of the key cylinder.
While the prior art locking operator cover secures the crank of the operator handle by covering it with the retractable sleeve, the retractable sleeve is fully visible and accessible from outside of the operator cover and may be subject to tampering because of this visibility and accessibility. Accordingly, there is still room for improvement in the lockable window operator arts.